webpack.config.js

const webpack = require('webpack');
const HappyPack = require('happypack');
const AutoDllPlugin = require('autodll-webpack-plugin');

module.exports = (storybookBaseConfig, configType) => {
  console.log('storybookBaseConfig.output', storybookBaseConfig.output);

  storybookBaseConfig.plugins = [
    new webpack.HotModuleReplacementPlugin(),
    new webpack.ProgressPlugin(),
    new HappyPack({
      loaders: ['babel-loader'],
    }),
  ];

  storybookBaseConfig.module.rules = [
    {
      test: /\.js$/,
      loaders: ['cache-loader', 'happypack/loader'],
      exclude: /dist|node_modules/,
    },
  ];

  console.log(
    'storybookBaseConfig.modules.rules',
    storybookBaseConfig.module.rules
  );

  return storybookBaseConfig;
};